I. Field of the Invention
The present invention relates generally to roller conveyors and, more particularly, to a roller with torque overload release means.
II. Description of the Prior Art
In a roller conveyor system, a plurality of rollers are rotatably mounted to a frame and, together, define a conveyor track upon which articles are conveyed. One or more of the rollers are rotatably driven so that the driven rollers engage and propel the articles from one end and to the other end of the conveyor track.
In the event of a jam of the articles on the conveyor track, it is highly desirable that the power driven rollers disengage or stop rotating in order to prevent damage to the articles and/or conveyor system which might otherwise occur. For this reason, there have been a number of previously known conveyor rollers with torque overload release clutches which enable the conveyor rollers to remain stationary when the torque between the conveyor roller and its drive means exceeds a predetermined amount. The previously known roller conveyor systems of this type are known as accumulating roller conveyor systems.
Many of the previously known torque limiting clutches for roller conveyors employ a helical spring which is variably compressed in order to create a frictional engagement between the drive means and the conveyor roller. The previously known clutches of this type, however, are relatively difficult to adjust in the field. Furthermore, in many cases, a different helical spring is required in order to obtain the desired torque drive between the conveyor drive means and the conveyor roller which requires replacement of the helical springs. Such replacement is not only time consuming and expensive, but in many cases the replacement springs are not readily available.
A still further disadvantage of the previously known conveyor roller is that the roller is of a fixed length and is designed for a particular load. In many situations, however, it is desirable to adjust the effective length of the roller conveyor in order to accommodate different types of articles.